Most of existing counterweights devices are using counterweights as the load. Due to the configuration of counterweights being affected by the space, the direction, the cost and many other factors, and thus there are disadvantages of a huge volume, a high cost, and a high transportation cost, which is unfavorable for the widespread popularity. For example, counterweights portion of the traditional fitness equipment is usually made up of multiple counterweights. The design can only be carried out by way of laminating, and the gravity is adjusted by increasing or decreasing the number of the counterweights. Thus, the height and the adjustment precision of the gravity of the fitness equipment are limited, easily leading to a problem, i.e., it is heavier with one more counterweight while it is lighter with one less counterweight. It is not easy for some types of the fitness equipment to switch the different gravities when multiple people are using at the same time.
Chinese patent CN201643528U discloses an automatic counterweighting mechanism for a strength-type fitness equipment, which is controlled by the micro-chips to select the counterweights automatically. It includes two parallel guide shafts, and the counterweights passing though the guide shafts from top to bottom are arranged in sequence to form a counterweights unit. A counterweight lead screw nut is embedded at the center of each counterweight. The top first counterweight of the counterweights unit is equipped with a counterweights automatic selecting mechanism. The counterweights automatic selecting mechanism includes a motor, a gearbox and a lead screw. The lead screw is vertically arranged, and the lead screw is engaged with the counterweight lead screw nut at the center of the counterweights.